Corylus plant named ‘McDonald’

ABSTRACT

A new and distinct  Corylus  plant named ‘McDonald’ characterized by moderate vigor and upright-spreading plant habit, yellowish-green developing and fully expanded leaves during the spring and summer, resistance to eastern filbert blight caused by the fungus  Anisogramma anomala  (Peck) E. Müller, presence of random amplified polymorphic DNA markers 152-800 and 268-580 in DNA, expression of incompatibility alleles S 2  and S 15  in the styles, and DNA fingerprints at 14 of 21 microsatellite marker loci differ from both parents, ‘Tonda Pacifica’ and ‘Santiam’, and from one parent at an additional 5 marker loci.

ACKNOWLEDGMENT OF GOVERNMENT SUPPORT

This invention was made with government support under Specific Cooperative Agreement No. 58-5358-4542 awarded by the United States Department of Agriculture. The government has certain rights in the invention.

Botanical denomination: Corylus avellana cultivar.

Variety designation: ‘McDonald’.

BACKGROUND

The present Invention relates to a new and distinct cultivar of Corylus plant, botanically known as Corylus avellana, and hereinafter referred to by the name ‘McDonald’.

The new Corylus resulted from a controlled cross of female parent ‘Tonda Pacifica’ (U.S. Plant Pat. No. 22,715) and male parent ‘Santiam’ (unpatented) made in 1997. Hybrid seeds from the cross were harvested in August 1997, stratified, and seedlings grown in the greenhouse during the summer of 1998. From this cross, a total of 132 seedling trees were planted in the field in Corvallis in October, 1998. ‘McDonald’ was discovered and selected as a single plant within the progeny of the stated cross-pollination in a controlled environment in Corvallis, Oreg., USA. It was originally assigned the designation OSU 880.027, which indicates the row and tree location of the original seedling.

‘Tonda Pacifica’ (OSU 228.084) was released in 2010 (Mehlenbacher et al., 2011), is from a cross of ‘Tonda Gentile delle Langhe’×OSU 23.024 (=‘Barcelona’×‘Extra Ghiaghli’). ‘Santiam’ (Mehlenbacher et al., 2007), released in 2005, carries a dominant allele for a very high level of resistance to eastern filbert blight (EFB) from ‘Gasaway’ (unpatented). ‘Tonda Gentile delle Langhe’ (unpatented), the female parent of ‘Tonda Pacifica’, is an important cultivar in Piemonte, northern Italy. ‘Barcelona’ (unpatented), Oregon's most widely planted hazelnut cultivar, is known as ‘Castanyera’ where it originated in Catalunya, Spain. ‘Extra Ghiaghli’ (unpatented), obtained from Greece, is a clone of the important Turkish cultivar ‘Tombul’. ‘Gasaway’ (unpatented) is the source of a single dominant gene for resistance to eastern filbert blight.

The new cultivar was asexually reproduced by rooted suckers annually for nine years (2004-2005, 2007-2013) in Corvallis, Oreg. The new cultivar was also asexually propagated by whip grafting in 2005 in Corvallis, Oreg. The unique features of this new Corylus are stable and reproduced true-to-type in successive generations of asexual reproduction.

SUMMARY

The following traits have been observed and are determined to be the unique characteristics of ‘McDonald’. These characteristics in combination distinguish ‘McDonald’ as a new and distinct cultivar:

-   -   1. Moderate vigor and upright-spreading plant habit.     -   2. Yellowish-green developing and fully expanded leaves during         the spring and summer.     -   3. Resistance to eastern filbert blight caused by the fungus         Anisogramma anomala (Peck) E. Müller.     -   4. Presence of random amplified polymorphic DNA markers 152-800         and 268-580 in DNA of ‘McDonald’ amplified by the polymerase         chain reaction. These two markers are linked to a dominant         allele for resistance to eastern filbert blight from the         cultivar ‘Gasaway’ (unpatented).     -   5. Expression of incompatibility alleles S₂ and S₁₅ in the         styles.     -   6. DNA fingerprints at 14 of 21 microsatellite marker loci         differ from both parents, ‘Tonda Pacifica’ and ‘Santiam’, and         from one parent at an additional 5 marker loci. Additional DNA         fingerprints of grandparent ‘Tonda Gentile delle Langhe’,         standard cultivar ‘Barcelona’, eastern filbert blight resistance         source ‘Gasaway’ and five cultivars released by Oregon State         University hazelnut breeding program are shown in Table 6.

Comparisons in two replicated trials conducted in Corvallis, Oreg., plants of the new Corylus differed from plants of the Corylus avellana cultivar ‘Barcelona’ and other cultivars and selections of Corylus avellana known to the Inventors primarily in nut size, nut shape, kernel percentage (ratio of kernel weight to nut weight), frequency of defects (blank nuts, moldy kernels, twins, etc.), time of pollen shed, time of nut maturity, length of the husk or involucre, and plant size. For example:

-   -   Blank nut frequency: ‘McDonald’ 2.7% in first trial, 5.1% in         second trial, %, ‘Barcelona’ 7.7% in first trial and 7.1% in         second trial;     -   Pollen shed: ‘McDonald’ sheds pollen with ‘Dorris’, ‘Wepster’         and ‘Yamhill’, slightly later than ‘Tonda Pacifica’, and         slightly earlier than ‘Sacajawea’, ‘Yamhill’ and ‘York’.         ‘McDonald’ descriptor=5;     -   Nut maturity: ‘McDonald’ nuts mature 14 days earlier than         ‘Barcelona’; and     -   Husk Length: ‘McDonald’ 1.5 times nut length, same as         ‘Barcelona’, while ‘Wepster’ is 2 times nut length.

‘McDonald’ is well-suited to the blanched kernel market for use in chocolate products and baked goods. ‘McDonald’ combines high nut yield, early nut maturity, small round nuts and kernels, high kernel percentage, good kernel blanching and excellent flavor. The tree is moderately vigorous and has a desirable growth habit.

DNA markers and field observations indicate that ‘McDonald’ has a very high level of resistance to eastern filbert blight (EFB) caused by the fungus Anisogramma anomala (Peck) E. Müller. The resistance is conferred by a dominant allele from ‘Gasaway’. EFB is now present throughout the Willamette Valley where 99% of the U.S. hazelnut crop is grown. Pruning to remove cankers and fungicide applications are currently used to manage the disease in orchards of ‘Barcelona’ and other susceptible cultivars. Thus, ‘McDonald’ is suitable for planting in areas with high disease pressure, as are previous releases ‘Santiam’ (2005), ‘Yamhill’ (2008, unpatented), ‘Jefferson’ (2009, unpatented), ‘Dorris’ (2012, U.S. Plant Pat. No. 25,022) and ‘Wepster’ (2013, U.S. Plant Pat. No. 27,141). ‘Wepster’, released as a cultivar in 2013, is cross-compatible with ‘McDonald’ in both directions. Thus ‘Wepster’ and ‘McDonald’ can be planted together with each serving as a pollinizer for the other.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying colored photographs illustrate the overall appearance of the new cultivar, showing the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Foliage colors in the photographs may differ slightly from the color values cited in the detailed botanical description which accurately describe the colors of the new Corylus.

FIG. 1 shows a tree the new cultivar ‘McDonald’ hazelnut in the 8th leaf.

FIG. 2 shows a tree of the new cultivar ‘McDonald’ hazelnut in winter at end of 7th leaf.

FIG. 3 shows a tree of the new cultivar ‘McDonald’ tree in winter at end of 7th leaf.

FIG. 4 shows August 2013 trees of the new cultivar ‘McDonald’ (left) and ‘Jefferson’ (right, unpatented), 8th leaf.

FIG. 5 shows trees of the new cultivar ‘McDonald’ (left) and ‘Wepster’ (right, unpatented), 8th leaf.

FIG. 6 shows nuts, husks and leaves of ‘McDonald’ hazelnut.

FIG. 7 shows nuts and husks of ‘McDonald’ hazelnut.

FIG. 8 shows nuts, raw kernels, and blanched kernels of hazelnuts ‘Wepster’ (OSU 894.030), ‘Yamhill’, ‘McDonald’ (OSU 880.027) and ‘Barcelona’.

FIG. 9 shows nuts, raw kernels and blanched kernels of hazelnuts ‘Yamhill’, ‘McDonald’ (OSU 880.027) and ‘Barcelona’.

FIG. 10 shows nuts, raw kernels and blanched kernels of hazelnuts ‘McDonald’ (OSU 880.027) and ‘Barcelona’.

FIG. 11 is a graph showing maturity of ‘McDonald’ (OSU 880.027) and ‘Barcelona’ based on percentage of nuts on the ground. Four trees of each genotype were harvested in 2013 on four dates (September 13, September 20, September 27 and October 4). Percentages of nuts on the ground based on weight are cumulative.

FIGS. 12A-12B show a phenology chart showing time of female receptivity (bottom, red) and pollen shed (top, green) of ‘McDonald’ (OSU 880.027) and other hazelnut cultivars (December 2011-March 2012).

FIGS. 13A-13D show a phenology chart showing bloom stage and pollen shed of hazelnut cultivars, pollinizers and selections (December 2012-March 2013).

DETAILED DESCRIPTION

The cultivar ‘McDonald’ has not been observed under all possible environmental conditions. The phenotype may vary somewhat with variations in environment such as temperature and light intensity, without, however, any variance in genotype. The aforementioned photographs and following observations and measurements describe plants grown in Corvallis, Oreg. under commercial practice outdoors in the field during the fall, winter and spring. Plants used for the photographs and description were propagated by tie-off layerage and growing on their own roots, and seven or eight years old. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 1966 Edition, except where general terms of ordinary dictionary significance are used. The list of UPOV descriptors are from the Mar. 28, 1979 Hazelnut guidelines from UPOV.

-   Botanical classification: Corylus avellana cultivar ‘McDonald’. -   Parentage:     -   -   Female, or seed, parent.—Corylus avellana cultivar ‘Tonda             Pacifica’ (U.S. Plant Pat. No. 22,715). ‘McDonald’ is             resistant to eastern filbert blight, while ‘Tonda Pacifica’             is highly susceptible. ‘McDonald’ and ‘Tonda Pacifica’ have             different alleles at 16 of the 21 microsatellite markers             loci. ‘McDonald’ has incompatibility alleles 2 and 15.             ‘Tonda Pacifica’ and ‘Wepster’ have alleles 1 and 2.             ‘McDonald’ has a shorter husk than ‘Tonda Pacifica’ and             earlier nut maturity.         -   Male, or pollen, parent.—Corylus avellana cultivar ‘Santiam’             (unpatented). -   Propagation (type rooted suckers):     -   -   Time to initiate roots.—About 30 days at 20° C.         -   Time to produce a rooted young plant.—About six months at             22° C.         -   Root description.—Fine to thick; freely branching; creamy             white in color. -   Propagation (type whip grafting):     -   -   Time to budbreak on the scions.—About 14 days at 25° C.         -   Time to produce a grafted plant.—About six months at 25° C. -   Plant description:     -   -   General appearance.—Natural habit is perennial shrub, but in             commercial orchards, is a single trunk tree.             Upright-spreading plant habit.         -   Growth and branching habit.—Freely branching; about 15             lateral branches develop per plant. Pinching, that is,             removal of the terminal apices, enhances branching with             lateral branches potentially forming at every node.         -   Vigor.—Moderate vigor growth habit.         -   Size.—Plant height is about 5 meters; plant diameter or             spread is about 5 meters.         -   Trunk.—At 30 cm above the soil line, 10.52 cm in 2007. -   Lateral branch description:     -   -   Length.—About 33.5 cm.         -   Diameter.—About 5 mm.         -   Internode length.—About 3.2 cm.         -   Texture.—Smooth, glabrous.         -   Strength.—Strong. Color, immature: 139D.         -   Color, mature.—177D. -   Foliage description:     -   -   Arrangement.—Alternate, simple.         -   Length.—About 10.4 cm.         -   Width.—About 8.7 cm.         -   Shape.—Oblong to ovate.         -   Apex.—Obtuse to acute.         -   Base.—Cordate.         -   Margin.—Serrate.         -   Texture, upper and lower surfaces.—Slightly pubescent.         -   Venation pattern.—Pinnate.         -   Color.—Developing foliage, upper surface 141C, lower             surfaces: 139C. Fully expanded foliage, upper surface:             Spring and summer, 139B; late summer and fall, 139B. Fully             expanded foliage, lower surface: Spring and summer, 139C;             late summer and fall, 139C. Venation, upper surface: Spring             and summer, 139C; late summer and fall, 139C. Venation,             lower surface: Spring and summer, 139D; late summer and             fall, 139D. -   Leaf but description:     -   -   Shape.—Globular.         -   Time of leaf budbreak.—Descriptor=6 (medium to late).             ‘McDonald’ leaf budbreak one week before ‘Dorris’, ‘York’             and ‘Wepster’; 4 days later than ‘Tonda Pacifica’ and             ‘Sacajawea’.         -   Color.—178C. -   Petiole description:     -   -   Length.—About 2.7 cm.         -   Diameter.—About 1.8 mm.         -   Texture, upper and lower surfaces.—Pubescent.         -   Color, upper surface.—Spring and summer, 139D; late summer             and fall, 139D.         -   Color, lower surface.—Spring and summer, 139D; late summer             and fall, 139D. -   Flower description: Male inflorescences are catkins, color prior to     elongation 176D. Catkin length 31.7 mm. Female inflorescence style     color 047B.     -   -   Time of female flowering.—Descriptor=5 (medium).         -   Time of female flowering compared to male             flowering.—Protogyny (descriptor=1, earlier).         -   Involucre constriction.—Absent.         -   Involucre length.—1.5 times length of nut, descriptor=5.         -   Size of indentation.—Descriptor=7 (strong).         -   Strength of serration of indentation.—Descriptor=7 (strong).         -   Pubescence on husk.—Descriptor=9 (present).         -   Thickness of callus at base.—Descriptor=5 (medium).         -   Jointing of bracts.—Descriptor=2 (on one side). -   Nut description:     -   -   Length.—About 18.4 mm.         -   Width.—About 18.9 mm.         -   Depth.—About 17.9 mm.         -   Nut shape.—Round. Nut shape index             [(Width+Depth)/2*Length]=1.00. Nut compression index             (Width/Depth)=1.05.         -   Nut shell color.—164A. Nut weight: About 2.51 grams.         -   Kernel weight.—About 1.29 grams.         -   Kernel percentage (kernel weight/nut weight).—About 51.5%.         -   Number of fruits per cluster.—Two to three.         -   Nut shell coloration.—164A.         -   Number of stripes on shell.—Descriptor=3 (few).         -   Prominence of fruit apex.—Medium prominent, descriptor=5.         -   Size of fruit pistil scar on shell.—Very small,             descriptor=3.         -   Hairiness of top of fruit.—Weak, descriptor=3.         -   Curvature of nut basal scar.—Flat.         -   Double kernels.—Absent.         -   Kernel shape.—Globular.         -   Shape of kernel in cross-section.—Circular.         -   Lateral groove in kernel.—Absent.         -   Corkiness of pellicle of kernel.—Rating 2.6 (vs. 3.0 for             ‘Jefferson’); descriptor=4 (slight to medium corky).         -   Nut yield (pounds per tree or per acre).—Total 17.11 kg per             tree in first trial, 21.43 kg per tree in second trial.         -   Storability of fruits.—Excellent, similar to OSU releases             and check cultivars. -   Disease/pest resistance: Plants of the new Corylus are highly     resistant to eastern filbert blight caused by the fungus Anisogramma     anomala (Peck) E. Müller, although a few small cankers may develop     under high disease pressure. Plants of the new Corylus are resistant     to bud mites (Phytoptus avellanae Nal.), while plants of ‘Tonda     Gentile delle Langhe’ are highly susceptible, and plants of     ‘Barcelona’ are highly resistant. -   Temperature tolerance: Plants of the new Corylus have been observed     to tolerate temperatures from −21 to 38° C. in the field in     Corvallis, Oreg.

COMPARATIVE DATA

Tree size, growth habit, yield, and yield efficiency Tree sizes in the two trials were estimated by measuring trunk diameters 30 cm above the soil line, at the end of the 7^(th) growing season (December 2012 and 2013, respectively). Trunk cross-sectional area (TCA) was calculated from trunk diameter. Trees of ‘McDonald’ are moderately vigorous, and their upright-spreading growth habit should be grower-friendly (easy to manage).

In the first trial (Table 1), TCA of ‘McDonald’ (86.9 cm²) was similar to ‘Jefferson’ (unpatented), ‘Dorris’, and ‘York’ (U.S. Plant Pat. No. 24,972). Trees were larger than ‘Yamhill’ (unpatented) but smaller than ‘Wepster’. Total nut yield per tree was 17.11 kg, which is slightly less than ‘Jefferson’, ‘Yamhill’ and ‘Wepster’ and about the same as ‘Dorris’ and ‘Sacajawea’ (unpatented). Nut yield efficiency of ‘McDonald’ (0.198 kg/cm²) was similar to ‘Sacajawea’ and ‘Wepster’, and lower than ‘Jefferson’ and ‘Yamhill’.

In the second trial (Table 1), trees of ‘McDonald’ were similar in size to ‘Jefferson’. In adjacent rows planted at the same time to EFB-susceptible selections, TCAs for ‘Barcelona’, ‘Lewis’ and ‘Clark’ were 138.6, 77.6 and 63.7 cm², respectively. The TCA of ‘McDonald’ is 63% of ‘Barcelona’. In previous trials, tree size of ‘Jefferson’ and ‘Lewis’ has been about 70% of ‘Barcelona’. Growers have been pleased with this level of vigor. Total nut yield per tree was 21.43 kg for ‘McDonald’ vs. 22.99 kg for ‘Jefferson’, 16.88 kg for the pollinizer ‘Felix’ (U.S. Plant Pat. No. 24,973), and 17.68 kg for ‘Santiam’. Nut yield efficiency for ‘McDonald’7 (0.245 kg/cm²), which adjusts for differences in tree size, was similar to ‘Santiam’ (0.267 kg/cm²), lower than ‘Jefferson’ (0.299 kg/cm²) and higher than ‘Felix’ (0.133 kg/cm²).

TABLE 1 Nut yield, trunk cross-sectional area, and yield efficiency of ‘McDonald’ and other hazelnut cultivars and selections in two trials No. Yield per tree (kg) Cultivar trees Year 3 Year 4 Year 5 Year 6 First trial (2006 planting) OSU 833.082 7 0.71 2.60 2.25 5.95 OSU 879.031 7 0.31 1.42 2.13 5.17 ‘McDonald’ 7 0.29 1.13 2.44 6.54 OSU 881.078 7 0.23 1.08 2.08 5.08 Dorris 7 0.42 2.84 3.30 6.51 Jefferson 7 0.41 3.55 3.35 6.97 Sacajawea 7 0.26 1.92 2.51 6.52 Santiam 7 0.29 1.76 3.73 7.25 Wepster 7 0.24 1.56 2.56 6.62 Yamhill 7 0.78 2.79 3.88 7.34 York 7 0.41 1.52 2.48 6.13 LSD_(0.05) 0.17 0.55 0.75 0.89 Second trial (2007 planting) ‘McDonald’ 4 0.15 1.10 4.85 7.38 Felix 4 0.06 1.04 2.91 7.93 Jefferson 4 0.55 1.97 5.63 4.60 Santiam 4 0.20 1.11 4.09 5.46 LSD_(0.05) 0.21 0.43 0.54 2.04 No. Yield per tree (kg) TCA^(z) YE^(y) Cultivar trees Year 7 Total (cm²) (kg · cm⁻²) First trial (2006 planting) OSU 833.082 7 2.46 13.97 68.1 0.205 OSU 879.031 7 6.54 15.58 87.2 0.179 ‘McDonald’ 7 6.71 17.11 86.9 0.198 OSU 881.078 7 6.67 15.15 112.4 0.135 Dorris 7 5.70 18.78 84.0 0.225 Jefferson 7 5.79 20.07 85.4 0.235 Sacajawea 7 6.76 17.97 93.7 0.196 Santiam 7 6.34 19.36 79.2 0.244 Wepster 7 8.68 19.67 99.2 0.198 Yamhill 7 4.94 19.73 78.5 0.249 York 7 4.42 14.97 85.6 0.175 LSD_(0.05) 1.26  2.62 10.4 0.027 Second trial (2007 planting) ‘McDonald’ 4 7.95 21.43 87.55 0.245 Felix 4 4.95 16.88 128.43 0.133 Jefferson 4 10.25 22.99 77.52 0.299 Santiam 4 6.83 17.68 66.81 0.267 LSD_(0.05) 1.18  2.45 13.48 0.029 ^(z)Trunk cross-sectional area calculated from trunk diameters measured in late fall at the end of the seventh season. ^(y)Yield efficiency = Total nut yield/TCA.

A high percentage of the nuts and kernels of ‘McDonald’ in both trials were marketable (Table 2). Very few moldy kernels were observed in ‘McDonald’, in striking contrast to ‘Santiam’.

TABLE 2 Frequency of good nuts, and of nut and kernel defects in ‘McDonald; and other hazelnut cultivars and selections in trials planted in 2006 and 2007 Frequency (%)^(z) Selection Good Blanks Brown stain Moldy First trial (n = 7) OSU 879.031 92.7 3.7 0.4 1.0 ‘McDonald’ 88.0 2.7 0.0 1.0 OSU 881.078 84.7 8.9 0.0 2.1 OSU 833.082 87.0 4.4 0.0 4.0 Dorris 80.7 7.5 0.2 4.2 Jefferson 84.2 3.8 0.1 4.4 Sacajawea 87.8 3.1 0.0 3.4 Wepster 86.7 7.6 0.2 1.1 Yamhill 91.3 2.3 0.1 2.2 York 83.7 8.7 0.3 1.7 Santiam 76.2 3.0 0.0 7.9 LSD_(0.05)  5.6 3.6 0.9 2.2 Second trial (n = 4) ‘McDonald’ 83.5 5.1 0.1 2.1 Felix 88.9 4.2 0.2 2.1 Jefferson 80.1 4.3 0.3 5.7 Santiam 68.8 2.8 0.1 17.3  LSD_(0.05)  3.5 2.5 0.3 2.3 Frequency (%)^(z) Selection Shrivel Poor fill Twins Black tips First trial (n = 7) OSU 879.031 1.0 0.6 0.3 0.3 ‘McDonald’ 7.5 0.5 0.0 0.3 OSU 881.078 2.8 1.1 0.1 0.3 OSU 833.082 2.8 0.7 0.5 0.6 Dorris 4.3 1.9 0.1 1.2 Jefferson 2.8 3.8 0.5 0.5 Sacajawea 3.1 1.2 0.1 1.3 Wepster 2.7 1.4 0.1 0.3 Yamhill 2.5 1.6 0.0 0.1 York 2.8 1.2 0.0 1.6 Santiam 9.4 2.3 0.2 0.9 LSD_(0.05) 2.7 2.3 0.5 0.9 Second trial (n = 4) ‘McDonald’ 4.5 4.5 0.1 0.3 Felix 0.4 2.9 0.3 1.1 Jefferson 0.4 8.9 0.6 0.6 Santiam 1.8 9.6 0.1 0.1 LSD_(0.05) 1.0 2.5 0.4 0.5 ^(z)Means of years 4-7. LSD = least significant difference.

Percent kernel (the ratio of kernel weight to nut weight) for ‘McDonald’ (52%) is higher than ‘Barcelona’ (typically 43%) and ‘Jefferson’ (45%) (Table 3). Yields of kernels per acre would be high for ‘McDonald’. Although ‘McDonald’ is not the highest-yielding selection, its yields have been consistently good and the nuts consistently well-filled. In contrast, ‘Yamhill’ trees occasionally set very heavy nut crops, and the nuts can be so poorly filled that the kernels are not marketable.

TABLE 3 Nut and kernel weight, kernel percentage, and ratings for fiber, blanching and bud mite susceptibility for ‘McDonald’and other hazelnut cultivars and selections in two trials. Nut Kernel Kernel Blanch- Bud Selection wt (g)^(z) wt (g) percentage Fiber^(y) ing^(x) mite^(w) First trial (n = 7) OSU 879.031 2.34 1.15 49.0 — 5.2 — McDonald’ 2.39 1.21 50.7 — 3.8 — OSU 881.078 2.37 0.97 41.0 — 4.5 — OSU 833.082 2.72 1.12 41.3 — 2.6 — Dorris 3.24 1.32 40.8 — 2.9 — Jefferson 3.53 1.51 42.8 — 4.8 — Sacajawea 2.52 1.29 51.2 — 2.8 — Santiam 2.09 1.03 49.5 — 5.1 — Wepster 2.23 0.98 43.9 — 3.1 — Yamhill 2.18 1.01 46.4 — 5.0 — York 2.59 1.12 43.4 — 4.8 — LSD_(0.05) 0.23 0.13  3.0 — 0.7 — Second trial (n = 4) ‘McDonald’ 2.62 1.37 52.3 2.6 3.3 1.8 Felix 2.71 1.37 50.8 3.0 2.2 2.0 Jefferson 3.76 1.67 44.5 3.0 4.3 1.2 Santiam 2.28 1.15 50.6 3.0 4.2 2.2 LSD_(0.05) 0.22 0.04  1.0 0.1 0.4 0.2 ^(z)Means for nuts and kernels are over four years. ^(y)Amount of fiber on the pellicle was rated in the second trial from 1 (none) to 4 (much). ^(x)Blanching was rated from 1 (complete pellicle removal) to 7 (no pellicle removal). ^(w)Susceptibility to bud mite (primarily Phytoptus avellanae Nal.) was rated on four trees of each selection in the second trial on a scale of 1 (no blasted buds) to 5 (many blasted buds). Shown are mean ratings for 5 years (2009-2013). LSD = least significant difference.

Nut maturity date. The nuts of ‘McDonald’ are borne in clusters of 2-3 in husks about 50% longer than the nuts. The husks are slit down the side, and flare open as they dry at maturity. About 95% of the nuts fall free of the husk at maturity (range 85-100%). The other 5% of the nuts would come out of the husks as they moved through the harvester. When mature, the shells are light tan in color. Harvest date is estimated to be 14 days before ‘Barcelona’, allowing it to be harvested before the start of the rainy season (Table 4 and FIG. 11).

TABLE 4 Harvest notes for four hazelnut genotypes harvested by hand for three years in the second trial. Year Selection Date Down^(z) Free^(y) 2010 ‘McDonald’ Sep. 28 88 99 Felix Oct. 12 87 77 Jefferson Oct. 12 86 78 Santiam Sep. 28 89 97 2011 ‘McDonald’ Oct. 27 96 93 Felix Oct. 27 96 81 Jefferson Oct. 27 88 64 Santiam Sep. 30 81 94 2012 ‘McDonald’ Oct. 4 97 98 Felix Oct. 18 85 84 Jefferson Oct. 18 81 89 Santiam Oct. 5 97 91 ^(z)Estimated percentage of nuts on the ground as opposed to in the tree. ^(y)Of the nuts on the ground, estimated percentage free of the husk.

Nuts in the first trial were annually raked and fed through a Mave harvester. Nuts in the second trial were hand-harvested and notes recorded at the time of harvest (Table 4). Notes included the date, the percentage of nuts on the ground (as opposed to in the tree), and the percentage of the nuts on the ground that were free of the husk (as opposed to inside the husk). We harvest more than 2000 trees by hand every fall, visiting a block once every 7 to 10 days, and harvesting a tree if >70% of the nuts are on the ground. Thus the percentages are estimates. The harvest dates and percentage down indicate that maturity of ‘McDonald’ is about 14 days earlier than ‘Barcelona’ (Table 4). To more precisely estimate nut maturity, the four trees of ‘McDonald’ in the second trial and four trees of ‘Barcelona’ in adjacent rows were harvested by hand at weekly intervals in the final year of the trial (2013). The maturity curves from the 2013 harvest (FIG. 11) show that nuts of ‘McDonald’ drop at least 14 days sooner than those of ‘Barcelona’. Most orchards planted since 2009 have been of ‘Jefferson’, which matures about three days after ‘Barcelona’. Plantings of ‘McDonald’ and ‘Wepster’ would allow harvest to begin two weeks earlier.

Nut and kernel characteristics: ‘McDonald’ can be used in the blanched kernel market as a companion for ‘Wepster’ and an alternative to ‘Yamhill’, ‘Lewis’, ‘Clark’ and ‘Sacajawea’. ‘McDonald’, like ‘Wepster’ and ‘Yamhill’, has a very high level of EFB resistance, while ‘Lewis’, ‘Clark’ and ‘Sacajawea’ have lower level of quantitative resistance. The nut shape is round with a slight point, which lends itself well to sizing and cracking. The shells are thin and easy to crack, and most kernels remain whole when the shell is broken. The kernel size of ‘McDonald’ is small, similar to ‘Clark’, and larger than ‘Wepster’. Raw kernels are attractive and have a light brown pellicle with a moderate amount of attached fiber (rating =2.6) on a scale of 1 (no fiber) to 4 (much fiber). Pellicle removal is rated on a scale of 1 (complete pellicle removal) to 7 (no pellicle removal), with ratings <4.0 being desired. Most of the pellicle on ‘McDonald’ kernels is removed from the kernels with dry heat in the blanching process (ratings=3.8 and 3.3 in the first and second trials, respectively) which is better than ‘Yamhill’ (rating=5.0). Kernel texture, flavor and aroma are excellent, and desirable for use in baked goods and chocolate products.

In two trials, ‘McDonald’ produced fewer nut and kernel defects (and more good kernels) than ‘Barcelona’ in adjacent rows. The nut and kernel data were similar in the two trials. The frequency of moldy kernels in ‘McDonald’ in the two trials was very low (1.0-2.1%) in contrast to ‘Jefferson’ (4.4-5.7%) and especially ‘Santiam’ (7.89-17.3%). Kernel mold is a problem in ‘Lewis’ and ‘Santiam’, particularly when weather is cool and wet in spring and early summer. The frequency of poorly filled nuts is low compared to other selections, even though ‘McDonald’ crops consistently well.

Incompatibility and pollinizers. The trees set a moderate to high amount of catkins that shed copious amounts of pollen in early mid-season, with ‘Wepster’, ‘York’ and ‘Yamhill’. Pollen has been collected and used in several controlled pollinations, and both quantity and viability appear to be very good. ‘McDonald’ has incompatibility alleles S₂ and S₁₅ as determined by fluorescence microscopy. Both alleles are expressed in the females, but only S₁₅ is expressed in the pollen because of dominance. By convention, alleles expressed in the pollen are underlined.

Time of pollen shed and female receptivity were recorded weekly from early December 2011 to late March 2013 (FIGS. 12A-12B). Female inflorescences of ‘McDonald’ emerged in early mid-season and were fully receptive in mid-January. ‘Wepster’ (S ¹ S₂) is recommended as a companion cultivar, as ‘Wepster’ and ‘McDonald’ are cross-compatible in both directions. At least one additional pollinizer that sheds compatible pollen in midseason and late-midseason is recommended. Suitable pollinizers include ‘York’ (S₂ S ²¹ ) and ‘Gamma’ (S₂ S ¹⁰ ). ‘Yamhill’ (S ⁸ S₂₆) is also a suitable pollinizer and is an attractive option as “temporary trees” in double-density plantings. Pollen of ‘Jefferson’ (S₁ S ³ ) is compatible on females of OSU 880.027, but the time of pollen shed is later than ideal. Pollen of ‘Dorris’ (S ¹ S ¹² ), ‘Sacajawea’ (S ¹ S₂₂) and ‘Barcelona’ (S ¹ S₂) is also compatible on females of OSU 880.027. Pollen of ‘Tonda di Giffoni’ (S ² S₂₃) is incompatible because it expresses S₂. Pollen of ‘Delta’ (S ¹ S ¹⁵ ), ‘Felix’ (S ¹⁵ S ²¹ ) and ‘Theta’ (S ⁵ S ¹⁵ ) is incompatible because of the shared allele S₁₅. Inclusion of ‘Wepster’ as a companion cultivar in the orchard results in no loss in total nut yield. Alternative orchard designs include plantings of different cross-compatible cultivars in adjacent rows. Flowering times will continue to be observed, and pollinizer recommendations adjusted accordingly. Pollinizers with a high level of EFB resistance would eliminate the need for fungicide control in the entire orchard.

Pests and diseases. Based on DNA marker data, ‘McDonald’, like ‘Wepster’ and ‘Yamhill’, has a very high level of resistance to EFB conferred by a dominant allele from ‘Gasaway’, so fungicide applications are not needed. RAPD markers 152-800 and 268-580 that flank the resistance allele in ‘Gasaway’ are present in ‘McDonald’, and these markers are transmitted to its seedlings. Additional RAPD markers linked to resistance are also present. Trees of ‘McDonald’ have not yet been challenged with the EFB pathogen in glasshouse or structure inoculations. No cankers have been observed on the 11 trees of ‘McDonald’ in the yield trials, while several cankers have been noted on adjacent trees of susceptible genotypes.

Susceptibility to bacterial blight caused by Xanthomonas campestris pv. corylina has not been quantified, but no trees in the two trials were affected.

Susceptibility to big bud mite (primarily Phytoptus avellanae Nal.) was rated in the second trial (Table 3) after leaf fall once per year for five years (December 2009-2013). The scale was from 1 (no blasted buds) to 5 (many blasted buds). The average ratings indicate adequate resistance for ‘McDonald’ (1.8), ‘Jefferson’ (1.2), ‘Felix’ (2.0) and ‘Santiam’ (2.2). Blasted buds are very rare on ‘McDonald’, so chemical applications should not be necessary to control bud mite.

Propagation: Layers of ‘McDonald’ are moderately vigorous and root well, but have lower vigor and caliper than those of ‘Jefferson’ and ‘Barcelona’.

DNA Fingerprinting: Primers used are shown in Table 5, and results shown in Table 6.

TABLE 5 Primers and annealing temperatures for the 21 microsatellite marker loci used to fingerprint ‘McDonald’ and other hazelnut cultivars. Primers 5′-3′ (Forward Locus Repeat motif Size above, Reverse below) T_(s) n He Ho PIC r LG Reference Locus A614 (TC)₁₇(CA)₁₀NNN(CA)₆ 125- Hex- 60 14 0.85 0.85 0.84 0.00 6 Gurcan et al. A999614 156 TGGCAGAGCTTTGTC 2010a AGCTT (SEQ ID NO: 1) R- GCAGTGGAGGATTGC TGACT (SEQ ID NO: 2) A616 (AC)₁₁ 136- Fam- 60 13 0.85 0.85 0.83 0.00 8 Gurcan et al. A616 162 CACTCATACCGCAAA 2010a CTCCA (SEQ ID NO: 3) R- ATGGCTTTTGCTTCGT TTTG (SEQ ID NO: 4) A640 (CT)₁₅(CA)₁₃ 354- F- 67 11 0.80 0.73 0.77 0.04 10 Gurcan et al. A640 378 TGCCTCTGCAGTTAG 2010a TCATCAAATGTAGG (SEQ ID NO: 5) Fam- CGCCATATAATTGGG ATGCTTGTTG (SEQ ID NO: 6) B619 (TC)₂₁ 146- Fam- 60 14 0.88 0.88 0.87 0.00 3 Gurcan et al. B619 180 AGTCGGCTCCCCTTT 2010a TCTC (SEQ ID NO: 7) R- GCGATCTGACCTCAT TTTTG (SEQ ID NO: 8) B634 (AG)₁₅ 218- Hex- 60 9 0.76 0.76 0.73 0.00 4 Gurcan et al. B634 238 CCTGCATCCAGGACT 2010a CATTA (SEQ ID NO: 9) R- GTGCAGAGGTTGCAC TCAAA (SEQ ID NO: 10) B671 (AG)₆NN(GA)₁₇ 221- Hex- 60 13 0.86 0.88 0.84 −0.01 9 Gurcan et al. B671 249 TTGCCAGTGCATACT 2010a CTGATG (SEQ ID NO: 11) R- ACCAGCTCTGGGCTT AACAC (SEQ ID NO: 12) B709 (GA)₂₁ 219- Ned- 60 8 0.74 0.76 0.70 0.01 5 Gurcan et al. B709 233 CCAAGCACGAATGAA 2010a CTCAA (SEQ ID NO: 13) R- GCGGGTTCTCGTTGT ACACT (SEQ ID NO: 14) B733 (TC)₁₅ 161- Ned- 60 8 0.68 0.68 0.63 0.00 7.2 Gurcan et al. B733 183 CACCCTCTTCACCAC 2010a CTCAT (SEQ ID NO: 15) R- CATCCCCTGTTGGAG TTTTC (SEQ ID NO: 16) B741 (GT)₅(GA)₁₂ 176- Fam- 60 10 0.77 0.78 0.74 0.00 5 Gurcan et al. B741 194 GTTCACAGGCTGTTG 2010a GGTTT (SEQ ID NO: 17) R- CGTGTTGCTCATGTG TTGTG (SEQ ID NO: 18) B749 (TC)₁₂ 200- Hex- 60 6 0.60 0.64 0.51 −0.03 1 Gurcan et al. B749 210 GGCTGACAACACAGC 2010a AGAAA (SEQ ID NO: 19) R- TCGGCTAGGGTTAGG GTTTT (SEQ ID NO: 20) B767 (TC)₁₅(AT)₇ 198- Fam- 60 16 0.87 0.80 0.86 0.04 8 Gurcan et al. B767 238 CCACCAACTGTTTCA 2010a CACCA (SEQ ID NO: 21) R- GCGAAATGGAGCTCT TGAAC (SEQ ID NO: 22) B774 (AG)₁₅ 195- Ned- 60 8 0.80 0.80 0.77 0.01 5 Gurcan et al. B774 213 GTTTTGCGAGCTCAT 2010a TGTCA (SEQ ID NO: 23) R- TGTGTGTGGTCTGTA GGCACT (SEQ ID NO: 24) B795 (TC)₈Ns(CT)₇Ns(CT)₁₀N 296- Fam- 60 12 0.76 0.74 0.74 0.01 9 Gurcan et al. B795 s(TC)₅ 332 GACCCACAAACAATA 2010a ACCTATCTC (SEQ ID NO: 25) R- TGGGCATCATCCAGG TCTA (SEQ ID NO: 26) C115 (TAA)₅(GAA)₁₂ 167- Fam- 60 14 0.80 0.80 0.77 0.00 4 Bassil et al. C115 226 ATTTTCCGCAGATAA 2005b, TACAGG (SEQ ID NO: Gokirmak et 27) al. 2009 GTTTCCAGATCTGCC TCCATATAAT (SEQ ID NO: 28) KG807 (TAAA)AA(TAAA)₂A 226- AAGCAAGAAAGGGA 54 4 0.67 0.78 0.60 −0.07 11 Gurcan and KG807 (TAAA)₂ 248 TGGT (SEQ ID NO: 29) Mehlenbacher 2010 FAM- CTTACAGATAAATGG CTCAAA (SEQ ID NO: 30) KG809 (AGG)₆ 333- Hex- 55 5 0.66 0.64 0.60 0.01 4 Gurcan and KG809 345 AGGCATCAGTTCATC Mehlenbacher CAA (SEQ ID NO: 31) 2010 F- GGAAGGTGAGAGAA ATCAAGT (SEQ ID NO: 32) KG811 (GA)₁₇ 240- Ned- 58 12 0.83 0.82 0.81 0.01 2 Gurcan and KG811 278 AAGGCGGCACTCGCT Mehlenbacher CAC(SEQ ID NO: 33) 2010 F- GAACAACTGAAGAC AGCAAAG (SEQ ID NO: 34) KG827 (CT)₁₃AA(CA)₇ 264- Fam- 67 9 0.78 0.84 0.75 −0.04 9 Gurcan and KG827 282 AGAACTCCGACTAAT Mehlenbacher AATCCTAACCCTTGC 2010 (SEQ ID NO: 35) GAGGGAGCAAGTCA AAGTTGAGAAGAAA (SEQ ID NO: 36) KG830 (CT)₁₄GTATT(CA)₈ 279- Ned- 67 9 0.79 0.78 0.76 0.00 9 Gurcan and KG830 311 TGGAGGAAGTTTTGA Mehlenbacher ATGGTAGTAGAGGA 2010 (SEQ ID NO: 37) AAAGCAACTCATAGC TGAAGTCCAATCA (SEQ ID NO: 38) Soman- (AAT)₅ 193- Hex- 54 3 0.60 0.98 0.51 −0.27 NA unpublished Soman-G G 200 TGGCGTTGCAACATA TTCTC (SEQ ID NO: 39) (=856- R- MS1- GCCATCTTTAGAAAG 13) TTCGATACAG (SEQ ID NO: 40) Primers fluorescent tags are FAM, HEX and NED Ta annealing temperature (° C.) n number of alleles He expected heterozygosity Ho observed heterozygosity PIC polymorphism information content r estimated null allele frequency LG linkage group; NA = not yet assigned Reference for development and characterization

TABLE 6 Allele sizes in ‘McDonald’ and eight other hazelnut cultivars at 21 microsatellite loci. ‘Tonda ‘Tonda Gentile Locus ‘McDonald’ Pacifica’ ‘Santiam’ delle Langhe’ A614 135/158 135/150 132/158 125/135 A616 150/160 150/160 150/152 150/152 A640 362/368 368/374 355/362 355/368 B619 158/172 166/172 158/166 150/166 B634 222/228 228/228 222/236 228/228 B657 211/219 211/229 219/227 219/227 B671 229/237 229/239 225/237 239/243 B709 229/229 229/235 229/229 229/229 B733 173/175 173/175 175/181 173/175 B741 178/188 178/186 186/188 176/184 B749 207/209 207/209 209/209 207/209 B767 200/214 200/218 212/214 214/218 B774 203/213 203/207 209/213 203/211 B795 317/333 315/333 317/333 315/333 C115 174/197 174/183 194/197 174/174 KG807 252/252 228/252 242/252 238/252 KG809 339/339 339/342 339/342 339/342 KG811 245/267 245/257 257/267 257/267 KG827 272/284 270/284 272/272 268/278 KG830 291/295 291/295 291/295 291/295 Soman-G 196/200 196/200 196/200 196/200 Locus ‘Barcelona’ ‘Wepster’ ‘Yamhill’ ‘Dorris’ A614 125/132 135/158 132/158 132/158 A616 144/152 152/160 150/150 150/152 A640 355/374 368/374 355/368 372/374 B619 158/172 166/172 158/172 158/166 B634 228/228 228/228 236/236 228/228 B657 219/223 227/229 219/229 211/227 B671 225/229 239/249 225/243 229/249 B709 227/235 229/235 229/229 229/229 B733 173/175 173/175 181/185 173/181 B741 178/186 178/186 178/186 178/186 B749 209/209 207/209 209/209 207/207 B767 214/240 200/242 214/238 214/218 B774 203/207 203/207 203/211 203/207 B795 333/333 333/333 333/333 333/333 C115 174/194 183/194 197/216 194/216 KG807 238/252 252/252 230/252 242/252 KG809 339/339 342/342 348/348 339/348 KG811 261/267 257/257 251/261 257/267 KG827 282/284 270/282 268/282 272/284 KG830 291/295 295/305 291/295 295/297 Soman-G 196/200 196/200 196/200 196/200 Locus ‘York’ ‘Felix’ ‘Gasaway’ A614 124/158 138/143 143/158 A616 144/152 150/152 150/150 A640 363/374 368/372 362/368 B619 158/166 158/166 172/176 B634 228/236 228/236 222/234 B657 221/223 219/227 225/229 B671 243/249 229/237 237/249 B709 229/233 229/233 229/229 B733 173/181 175/181 175/175 B741 178/186 186/186 186/188 B749 209/209 207/207 207/209 B767 236/238 214/214 214/214 B774 203/209 203/213 203/209 B795 333/333 321/333 317/319 C115 197/197 197/216 216/219 KG807 242/252 238/242 242/252 KG809 339/348 339/348 339/348 KG811 257/257 251/267 257/261 KG827 268/272 272/284 272/282 KG830 295/295 293/303 291/305 Soman-G 196/200 196/200 196/196 ‘McDonald’ fingerprint same as both parents: 2 ‘McDonald’ fingerprint same as one parent: 5 ‘McDonald’ fingerprint different from both parents: 14

REFERENCES

-   Bassil N. V., Botta R., Mehlenbacher S. A. 2005a. Microsatellite     markers in hazelnut: Isolation, characterization and cross-species     amplification. J. Amer. Soc. Hort. Sci. 130:543-549. -   Bassil N. V., Botta R., Mehlenbacher S. A. 2005b. Additional     microsatellite markers of the European hazelnut. Acta Hort.     686:105-110. -   Bassil N., Boccacci P., Botta R., Postman J. and     Mehlenbacher S. A. 2012. Nuclear and chloroplast microsatellite     markers to assess genetic diversity and evolution in hazelnut     species, hybrids and cultivars. Genetic Resources and Crop Evolution     (on-line) DOI 10.1007/s 10722-012-9857-z -   Boccacci P., Akkak A., Bassil N. V., Mehlenbacher S. A.,     Botta R. 2005. Characterization and evaluation of microsatellite     loci in European hazelnut (C. avellana) and their transferability to     other Corylus species. Molec. Ecol. Notes 5:934-937. -   Boccacci P., Akkak, A. and Botta, R. 2006. DNA typing and genetic     relations among European hazelnut (Corylus avellana L.) cultivars     using microsatellite markers. Genome 49:598-611. -   Gökirmak T., Mehlenbacher S. A., Bassil N. V. 2009. Characterization     of European hazelnut (Corylus avellana) cultivars using SSR markers.     Genetic Resources and Crop Evolution 56:147-172. -   Gürcan, K. and S. A. Mehlenbacher. 2010. Transferability of     microsatellite markers in the Betulaceae. J. Amer. Soc. Hort. Sci.     135:159-173. -   Gürcan, K. and S. A. Mehlenbacher. 2010. Development of     microsatellite marker loci for European hazelnut (Corylus avellana     L.) from ISSR fragments. Molecular Breeding 26:551-559. (available     on-line as DOI 10.1007/s11032-010-9464-7) -   Gürcan, K., S. A. Mehlenbacher and V. Erdogan. 2010a. Genetic     diversity in hazelnut cultivars from Black Sea countries assessed     using SSR markers. Plant Breeding 129:422-434. (available on-line     doi :10. 1111/j. 1439-0523. 2009. 01753. x). -   Gürcan, K., S. A. Mehlenbacher, R. Botta and P. Boccacci. 2010b.     Development, characterization, segregation, and mapping of     microsatellite markers for European hazelnut (Corylus avellana L.)     from enriched genomic libraries and usefulness in genetic diversity     studies. Tree Genetics and Genomes 6:513-531. (available on-line as     DOI: 10.1007/s11295-010-0269-y) -   Mehlenbacher, S. A., D. C. Smith, R. L. McCluskey and M. M.     Thompson. 2011. ‘Tonda Pacifica’ hazelnut. HortScience 46:505-508. -   Mehlenbacher, S. A., A. N. Azarenko, D. C. Smith, and R. L.     McCluskey. 2007. ‘Santiam’ hazelnut. HortScience 42:715-717. -   Sathuvalli, V. R. and S. A. Mehlenbacher. 2012. Characterization of     American hazelnut (Corylus americana) accessions and Corylus     americana×Corylus avellana hybrids using microsatellite markers.     Genetic Resources and Crop Evolution 59:1055-1075. DOI     10.1007/s10722-011-9743-0. 

We claim:
 1. A new and distinct cultivar of Corylus plant as herein illustrated and described. 